Method of shaping sheet blanks to spherical form and a device to realize same

ABSTRACT

A BLANK IS CONTINOUSLY PASSED THROUGH GROUPS OF FREELY ROTATING ROLLERS LOCATED CIRCUMFERENTIALLY IN EACH GROUP AND ROTATING ALONG THESE CIRCUMFERENCES. THE AXES OF THE GROUPS LIE ON ONE PLANE AND INTEREST IN A POINT WHICH IS THE CENTER OF THE SPHERE, WITH THE ROLLERS BENDING THE BLANK CIRCUMFERENTIALLY AND SHAPING IT TO A SPHERICAL FORM. THE DEVICE COMPRISES A FORMING UNIT COMPOSED OF THREE ROTARY HEADS WITH BENDING ROLLERS. TWO HEADS WHOSE ROLLERS ARE DIRECTED TO ONE SIDE ARE ADJUSTABLE FOR THE RADIUS OF THE SPHERE TO BE PRODUCED, AND THE ROLLERS OF THE TWO THE THIRD HEAD ARE DIRECTED TOWARDS THE ROLLERS OF THE TWO HEADS, THUS FORMING A BENDING AND A BEARING GROUP OF DEFORMING ELEMENTS DIRECTED OPPOSITE EACH OTHER   D R A W I N G

F85. 1973 J. IVANOVI H HEIN 3,713,021

METHOD OF SHAPING SHEE BL NKS TO SPHERICAL FORM AND A DEVICE TO REALIZE SAME Filed Sept. 22. 1971 4 Sheets-Sheet 1 & M

W 45 19 1i M W I? I M Z z FIG 4 Feb. 27, 1973 J. IVANOVICH. 5H m 3,713,021

METHOD OF SHAPING SHEET BLANK TO SPHERIGAL FOR AND A DEVICE TO REALIZE SAME "Filed Sept. 22. 1971 4 SheetS -Sheet 2 3,718,021 TO SPHERICAL IZE SAM m SL um su H w v w V MGM A FGb. 27. 7" J METHOD OF SHA FORM AND 4 Sheets-Sheet 3 Filed Sept. 22. 1971 Feb,

Filed Sept. 22. 1971 J. IVANOVIC H EHEIN 3,718,021

METHOD OF PING SHEET BLANKS T0 ERICAL FORM A DEVICE TO REALIZE E 4 Sheets-Sheet United States Patent O 3,718,021 METHOD OF SHAPING SHEET BLANKS TO SPHERICAL FORM AND A DEVICE T REALIZE SAME Jury Ivanovich Shein, Volgograd, U.S.S.R., assignor to Vsesojuzny nauchnoissledovatelsky i proektny institur, Lenina, U.S.S.R.

Filed Sept. 22, 1971, Ser. No. 182,659 Claims priority, application U.S.S.R., Sept. 22, 1970, 1,478,325; Oct. 20, 1970, 1,484,912

Int. Cl. B2111 5/14 U.S. Cl. 72-126 5 Claims ABSTRACT OF THE DISCLOSURE A blank is continuously passed through groups of freely rotating rollers located circumferentially in each group and rotating along these circumferences. The axes of the groups lie in one plane and intersect in a point which is the center of the sphere, with the rollers bending the blank circumferentially and shaping it to a spherical form. The device comprises a forming unit composed of three rotary heads with bending rollers. Two heads whose rollers are directed to one side are adjustable for the radius of the sphere to be produced, and the rollers of the third head are directed towards the rollers of the two heads, thus forming a bending and a bearing group of deforming elements directed opposite each other.

BACKGROUND OF THE INVENTION The present invention relates to the pressure shaping of metals and, particularly, to methods of and devices for shaping sheet blanks to a spherical form.

This invention can most advantageously be employed for making the leaves of spherical vessels used in the chemical and oil industries. However, it can equally be employed to form spherical bottoms in the construction of chemical and oil apparatus, as well as in ship building.

Sheet blanks are, at present, shaped to spherical form by repeatedly acting on the blank with a deforming element.

The leaves of spherical vessels are known to be produced by a method of multiple pressing of the leaf elements in a punch and die, or by a method of bending in special spherical rolls.

The known methods and devices do not embody versatility, as a change to another type-and-size of the leaf involves a complete replacement of the costly equipment, and do not secure adequate quality of the leaves. Besides, producing the leaves from stainless and high-strength steels is quite difiicult due to the special properties of these steels.

The division of the leaf into elements to make it by the pressing method lengthens the perimeter of the curved welds and increases the labor consumption to assemble the spherical vessels.

An object of the present invention is to provide a method and a device which enable the deforming of a cold sheet blank to make leaves of spherical vessels from carbon, stainless, and high-strength steels.

Another object of the invention is to provide a method and a device, which ensure high quality of the leaves produced.

A further object of the invention is to provide a method and a device, which embody complete versatility.

SUMMARY OF THE INVENTION With these and other objects in view, in a method in which the blank is passed through deforming elements, according to the invention, the blank is continuously fed 3,718,021 Patented Feb. 27, 1973 through freely rotating deforming elements combined into groups, arranged circumferentially, and rotating along these circumferences, the axes of rotation of the groups lying in one plane and intersecting in a point which is the center of the sphere to be obtained, with the continuous feeding of the blank and the circumferential rotation of the deforming elements resulting in a circular bending, and shaping the blank to a spherical form.

In a device to realize this method, according to the invention, the forming unit includes three rotary heads having an identical form and each head carrying a group of deforming elements in the form of rollers disposed along circumferences concentric with the axes of rotation of each head, which axes lie in one plane and intersect in a point which is the center of the sphere to be produced, the axes of rotation of two heads adjustable for the radius of the sphere to be produced, whose deforming elements are directed to one side, being located symmetrically about the axis of rotation of the third head, whose deforming elements are directed towards the deforming elements of the first two heads, thus defining a bending group and a bearing group of deforming elements directed opposite each other.

Such a design permits making spherical parts, such as leaves of spherical vessels, from sheet blanks of carbon, stainless, high-strength, and other steels in a cold condition, which feature adequate quality at a high rate of production due to the forming unit being in the form of rotary heads provided with bending rollers adjustable to the radius of the required sphere.

To simplify the design of the device, the axes of rotation of the rollers in the two heads disposed symmetrically about the axis of rotation of the third head, and having their rollers directed to one side, intersect with tangents to the circumference of their location at an angle differing from a right angle, and the rollers are turned to one side so as to secure continuous feeding of the blank into the deformation zone.

To improve the quality of the spherical blank being formed, the rollers of all the heads are set normally to the tangent to the required blank sphere in the point of its contact with the roller.

In order to increase the force of feed and raise the production rate, the third rotary head is composed of two rotary components with bending rollers, one of the components being the driving component, and the other being the driven component, while the axes of rotation of the components are located at an angle to each other, so that when the rollers of one component contact the blank, the bending rollers of the other component are excluded from the contact. The value of the angle of intersection between the axes of rotation of the components is negligibly small, and is just sufficient to exclude the contact of a certain part of the rollers with the blank. The bending rollers of each of the components are turned to opposite sides, with the axes of rotation of all the bending rollers in each component intersecting with the tangents to the circumference of their location at an angle differing from a right angle.

For a better understanding of the invention, considered below is a particular exemplary embodiment of the device for producing the leaves of spherical vessels, with reference to the appended drawings, wherein:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows diagrammatically the sequence of the process to produce a leaf;

FIG. 2 is a general view partly in section and partly in elevation of the present device;

FIG. 3 is a view similar to FIG. 2, taken at right angles thereto;

FIG. 4 is a plan view partly in section of the device shown in FIG. 2;

FIG. is a front view partly in section illustrating the position of the bending rollers of the rotary heads when feeding the blank into the deformation zone;

FIG. 6 is a plan view of the arrangement shown in FIG. 5;

FIG. 7 is a view similar to FIG. 2 of another embodiment; and

FIG. 8 is a plan view partly in section of the device shown in FIG. 7.

DETAILED DESCRIPTION OF THE DRAWINGS The leaves of spherical vessels are made as follows.

A blank 1 (FIG. 1) is continuously fed into a zone of deformation formed by rollers 2, rollers 3, and rollers 4. Rollers 2, 3 and 4 are combined into groups in which they are disposed and rotate along circumferences. The group of rollers 2 is located opposite the groups of rollers 3 and 4.

The axes of rotation of the groups of rollers lie in one plane, and intersect in a point 0, which is the center of the sphere.

As a result of such disposition of the rollers and their circumferential rotation, and also due to the continuous blank feeding into the deformation zone, a circular bending is secured with shaping of the sheet blank to the required spherical form.

Circular bending makes it possible to deform sheet blanks of any required length.

The above-described method is realized by means of a device comprising a stand 5 (FIGS. 2, 3), in which is housed a forming unit defined by three rotary heads 6, 7, and 8, which are disposed so as to have their axes of rotation located in one plane, with the axes of rotation of heads 7 and 8 being positioned symmetrically about the axis of rotation of head 6. The rotary heads have bending rollers 9 disposed along circumferences concentric with the axes of rotation of each head, and freely rotating about their axles. Rollers 9 of head 6 are directed opposite rollers 9 of heads 7 and 8 which, in turn, are directed to one side, hence a bending group and bearing groups of rollers 9 directed opposite each other are provided.

The rotary head 6, which is the bearing head, receives rotation from an electric motor 10 through a reduction gear 11.

The rotary heads 7 and 8, which are the bending heads are mounted in a movable traverse 12, and are rotated in synchronism in opposite directions by an electric motor 13 (FIGS. 34) through a reduction gear 14, cardan shafts 15, and bevel gearings 16 (FIG. 2).

The adjustment of the bending heads 7 and 8 to the radius of the leaf sphere so that their axes of rotation intersect in the center of the leaf sphere being formed, is effected by turning the heads on semi-axles 17 (FIG. 3) secured in the traverse 12, through a worm gearing 18, with the heads being then fixed by any conventional method.

Vertical displacement of the movable traverse 12 with the bending heads 7 and 8 is accomplished via the electric motor 13 the reduction gear 14, a torsion shaft 19 (FIG. 4), a 'worm gearing 20 (FIG. 2), and a screw pair 21.

When passing to leaves of narrower width, the bending rollers are repositioned so as to reduce the radius of their movement. For this purpose, the rotary heads are fitted with additional slots 22 (FIG. 3).

The continuous feeding of the blank into the zone of deformation is effected by rolls 23 and 24 (FIG. 2) operating from separate drives, and each drive comprises an electric motor 25 (FIGS. 3-4), a reduction gear 26, and cardan shafts 27, with the rolls being adjustable for the blank entry and exit, and being fitted with an arrangement to press up the blank (not shown in the drawings).

The drive rolls 23, 24 complicate the design of the device, extend the time of adjustment and the operating cycle, and constitute the main disadvantage of the abovediscussed device.

To eliminate this disadvantage, the axes of rotation of rollers 9 in heads 7 and 8 intersect with the tangents to their location circumferences at an angle diifering from a right angle, with the rollers being all turned to one side.

This is achieved in that during the leaf bending there is no contact (see clearance a in FIGS. 5-6) between the blank and a certain part of rollers 9 in the bending heads 7 and 8.

Whereas in the process of bending, clearance a between a certain part of rollers 9 of heads 7 and 8, and blank 1 emerges due to the impossibility to obtain at once a leaf of the required radius, at the moment of completion of the leaf bending it appears due to the different values of the blank springing along the major and minor axes of the leaf. The latter factor necessitates overbending the blank along the major leaf axis.

In view of the different directions of rotation of heads 7 and 8, their rollers 9 are turned to one side. The clearance a at the certain part of the rollers provides a combined unidirectional force.

To improve the obtained quality of the spherical surface rollers 9 (FIG. 5) of all, the heads 6, 7 and 8 are turned so as to be normal to the tangent to the required sphere of blank 1 in the point of its contact with the roller. The turning mechanism might have any conventional design. This is turn helps to raise the force of feed.

To increase the force of feed and enhance the production rate, the rotary head 6 (FIGS. 7, 8) is formed of two rotary components 28 and 29 with bending rollers. The components 28 and 29 are placed in a housing 30 with their axes of rotation being disposed at an angle to each other and being symmetrical about the general axis of the device, so that during the contact of the bending rollers 9 of one component with blank 1, the bending rollers 9 of the other two components are excluded from the contact. The angle of intersection of the rotation axes of components 28 and 29 is very small, and is just sufiicient to exclude the contact of the part of the rollers with the blank. The bending rollers of components 28 and 29 are turned to opposite sides.

The axes of rotation of the bending rollers 9 in the components 28 and 29 intersect with the tangents to the circumferences of their location in each head at an angle different from a right angle. The rotary component 28 serves as the driver, and is rotated by the electric motor 10 through the reduction gear 11. The component 29 is driven by the driving head 28, both heads functioning as a clutch.

Vertical displacement of the rotary head 6 formed by the two heads 28 and 29 for placing blank 1 and springing it is eifected through a shaft 31, worm gearings 32, and screw pairs 33.

The rotary heads 7 and 8 are mounted in a housing 30 and are rotated in synchronism in opposite directions by an electric motor 34 through a reduction gear 35, cardan shafts 36, and bevel gearings 37.

Adjustment of heads 7 and 8 for the radius of the leaf sphere, so that their axes of rotation intersect in the center of the leaf sphere to be produced, is effected by turning the heads on semi-axles 38 mounted in the housing 30, and then fixing the heads by any conventional method.

The device operates as follows:

The rotary heads 7 and 8 (FIGS. 7, 8) are adjusted for the radius of the required sphere of leaf 1 by turning the heads on the semi-axles 38.

The bending rollers of all the heads are set normally to the tangent to the required sphere of blank 1 in the point of contact. The end of the sheet blank is passed between the bending rollers of the rotary heads 7, 8, and components 28, 29, and is sprung by the components 28, 29 in their vertical displacement from shaft 31 through the worm gearings 32 and the screw pairs 33.

Rotation of all the heads results in a circular bending of the sheet blank by the rollers of the heads, and a continuous feeding of the blank along the major axis of the leaf being formed. Having passed the blank in one direction, it is further sprung by components 28, 29 through their vertical displacement.

By changing the direction of rotation of all the rotary heads the direction of the blank feed into the deformation zone is changed, and so forth until obtaining the specified spherical form of the sheet blank, after which the leaf is removed. The cycle is then resumed.

For changing to another type-and-size of the leaf, it is sufiicient to turn the rotary heads 8 and 7 on the semiaxles 38 and setting the bending rollers in all the rotary heads normally to the tangent to the required sphere.

What is claimed is:

1. A method of shaping sheet blanks to spherical form, comprising continuously feeding a bank through freely rotating deforming elements, said elements being combined into oppositely disposed groups, circumferentially, and rotatable along these circumferences, with the axes of rotation of the groups lying in one plane and intersecting in a point which is a center of a sphere, whereby the continuous feeding of the blank and the circumferential rotation of the deforming elements provide for circular bending, and shape the blank to a spherical form.

2. A device for shaping sheet blanks to spherical form, comprising: three rotary heads of identical form constituting a forming unit, each head carrying deforming elements defined by rollers between which is passed a sheet blank which is shaped to spherical form as a result of the deformation process of the deforming elements, said rollers of two of said heads being directed to one side, said rollers of the third head being directed towards the rollers of said two heads, thus constituting bending and bearing groups of rollers directed opposite each other, said rollers in all the heads being located along circumferences concentric with the axes of rotation of all the heads lying in one plane and intersecting in a point which is a center of a sphere to be produced, said axes of the two heads with rollers directed to one side being disposed symmetrically about the axis of rotation of the third head, and said heads with rollers directed to one side being adjustable for the radius of the sphere to be obtained; and a means to adjust the heads for the sphere radius.

3. The device as in claim 2, wherein the axes of rotation of the rollers directed to one side intersect with tangents to their location circumferences at an angle differing from a right angle, said rollers being turned to one side so as to secure continuous blank feeding into the zone of deformation.

4. The device as in claim 2, wherein the rollers of all the heads are set normal to tangents to a sphere to be produced at their points of contact therewith.

5. A device for shaping sheet blanks to spherical form, comprising: three rotary heads of identical form constituting a forming unit, each head carrying deforming elements defined by rollers between which is passed a sheet blank which is shaped to spherical form 'as a result of the deformation process of the deforming element; said rollers of two of said heads being directed to one side, said third head including two rotary components provided with bending rollers, one of which is a driving component, and the other a driven component, said rollers in the driven and the driving components being directed towards the rollers of the first two heads thus forming a bending and a bearing groups of rollers directed opposite each other; said rollers in all the heads being located along circumferences concentric with the axes of rotation of these heads; said axes of rotation of the driven and the driving components being disposed at an angle to each other symmetrically about the general axis of the device, so that during the contact of the bending rollers of one of said components, either the driven or the driving component, with the blank, the bending rollers of the other component are excluded from the contact; said rollers in said driven and driving components being turned to opposite sides; the axes of rotation of the components with rollers directed to one side intersecting in a point which is a center of a sphere to be produced, and which is symmetrical about the general axis of the device; the axes of rotation of all said heads lying in one plane, and said heads will rollers directed to one side being adjustable for the radius of the sphere to be produced; and a means to adjust said heads for the sphere radius; the axes of rotation of all said rollers of all said heads intersecting with tangents to their location circumferences at an angle differing from a right angle.

References Cited UNITED STATES PATENTS 1,360,403 11/1920 Hollarn et al. 72l68 3,372,567 3/1968 Jensen et al. 72-80 MILTON S. MEHR, Primary Examiner U.S. Cl. X.R. 72168, 177 

